Various proposals have been made on a free viewpoint image generation technique and a display technique for reproducing an image at an arbitrary position from motion images captured by a plurality of cameras (for example, see Patent Literatures 1 to 4, Non-Patent Literature 1, and Non-Patent Literature 2).
These methods are referred to as image-based rendering. More specifically, a light field is constructed from the images captured by a plurality of cameras, and based on this light field, an image viewed from an arbitrary position is generated by using interpolating processing.
Incidentally, construction of the light field is a process of correlating a light ray passing through a certain plane, expressed as a coordinate in the coordinate space and the pixel value of this coordinate space. It is impractical to prepare pixel value data for the entire coordinates in the coordinate space in advance. So, usually the pixel data are prepared for a certain part of the coordinate, and the rest are decided by interpolation.
In order to display the free viewpoint picture in an effective manner, the user needs to get used to the handling of switching process. Patent Literature 5 discloses a recommended display method in the free viewpoint image generation technique in which a plurality of operation histories (e.g., viewpoint condition and elapsed time) of users similar in static attribute (e.g., sex, age, etc.) is stored and an average operation history determined on the basis of the plurality of operation histories is distributed as a recommended operation history to the users similar in static attribute (paragraphs 0062-0064).